Improvement in lifting-jacks



G. H. PLATT'.

, Lifting-Jacks.

N0.l49 604. Patented Aprl1 4,1874,

ATTORNEYS,

UNITED STATES PATENT OEEIcE GEORGE H. PLATT, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR OF PART OF HIS RIGHT TO JAMES R. HUNTER AND GEORGE W. HUNTER, OF

SAME PLACE.

IMPROVEMENT IN LlFTlNG-JACKS.v

Specification forming part of Letters Patent No. 149,604, dated April 14, 1874; application filed April 2, 1874.

To all whom it may concern:

Be it known that I, GEORGE H. PLATT, of Washington, in the District of Columbia, have invented a new and useful Improvement in Lifting-Jacks; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings forming a part of this specification, in which- Figure l is a front or plan view of the standardor support in elevation, and the lever at its lowest point. Fig. 2 representsa side view of the lever, slot, and the oog-wheel in position.

In Fig. l, Arepresents the standard or support connected with a suitable base, provided with an adjustable and sliding upright, B, in which are notches vb for the reception of the cogs d 011 the wheel D. C in the drawings represents a pawl, the purpose of which. in my invention is to secure or hold the sliding upright B at any desired point of elevation while the lifting-jack is being operated. D is an ordinary cog-wheel, and needs no description. E represents a lever, at the inner extremity of which, and on either side, are extensions or cars G G, in which are corresponding slots. The slots F Fin the extensions or ears G G diverge from the center or fulcrum upward and outward, for the reception of the axle their oflice being to allow the pawl e to become disconnected from the cogs d in the wheel D while the lever E is being raised. The slots F F are so arranged that, upon a downward movement of the lever, the pawl e in the lever becomes necessarily and immovably fixed between the cogs, and, by an upward movement of the lever, said pawl c becomes necessarily detached, which permits the lever to be raised for a new hold or purchase, without changing the position of the adjustable upright and cogwheel. The inner termination of the solid portion of the lever E forms the pawl e, which meshes in between the cogs for the purpose of forcingthe cog-wheel downward, thereby raising the adjustable and sliding upright B.

Having thus fully described my invention,

what I claim as new, and desire to secure by Letters Patent, is-

The lever E, provided with slotted ears G and pawl e, in combination with cog-wheel D, rackbar B, standard A, and pivoted pawl C, substantially as and for the purposes shown and described.

GEORGE H. PLATT.

Witnesses:

GEO. W. HUNTER, WARREN G. STONE. 

